Abstract

Aerosols and gaseous pollutants are transported in the atmosphere on a global scale. They are eventually removed by atmospheric dry and wet deposition, which provide nutrients (such as Fe and P) and/or toxins (such as Cu) to the land and marine ecosystems. This external flux of nutrients and/or toxins can affect the carbon cycle and the climate indirectly through affecting biogeochemical cycles in the most remote land and marine ecosystems, some of which are nutrient limited or sensitive to external inputs. Preliminary modeling studies show that the feedbacks in the carbon cycle resulted from land-atmosphere-ocean natural and anthropogenic interactions remain as a large fraction of the uncertainty in predicting climate change.

A number of parameters and processes need to be understood before we are able to quantify the indirect effect of atmospheric deposition on the climate. One of the key parameters is the flux of bioavailable nutrients to the ocean. Although global models agree relatively well (within a few times) on the flux of total dust to the oceans, it is not well constrained by measurements. More importantly, models are unable to agree on the orders of magnitude of the flux of bioavailable nutrients. This later parameter is dependent on the total content and the solubility of the nutrients in atmospheric depositions. I will talk on what we know on the factors controlling the solubility of nutrients in aerosol. I will further discuss what we are doing as well as what we need to do to improve the estimation of the bioavailable nutrients to the ocean.